CVE-2025-62425 in matrix-authentication-service
Summary
by MITRE • 10/16/2025
MAS (Matrix Authentication Service) is a user management and authentication service for Matrix homeservers, written and maintained by Element. A logic flaw in matrix-authentication-service 0.20.0 through 1.4.0 allows an attacker with access to an authenticated MAS session to perform sensitive operations without entering the current password. These include changing the current password, adding or removing an e-mail address and deactivating the account. The vulnerability only affects instances which have the local password database feature enabled (passwords section in the config). Patched in matrix-authentication-service 1.4.1.
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Analysis
by VulDB Data Team • 10/16/2025
The CVE-2025-62425 vulnerability represents a critical logic flaw in the Matrix Authentication Service that undermines the security of user authentication processes within Matrix homeservers. This vulnerability specifically targets instances where the local password database feature is enabled, creating a significant risk for users who maintain authenticated sessions with the service. The flaw exists in versions 0.20.0 through 1.4.0 of the matrix-authentication-service, making it a widespread concern for organizations and individuals using Element's authentication service. The vulnerability's impact extends beyond simple credential theft, as it allows attackers to perform sensitive account operations that would normally require password verification, effectively bypassing the fundamental security principle of multi-factor authentication and password confirmation.
The technical implementation of this vulnerability stems from improper session validation mechanisms within the authentication service. When a user maintains an authenticated session, the system should enforce password re-verification for sensitive operations to prevent unauthorized changes to account credentials. However, the flaw in the MAS service allows attackers who have already obtained session access to execute privileged actions without re-authenticating through the password verification process. This represents a direct violation of the principle of least privilege and demonstrates a critical failure in the service's access control implementation. The vulnerability specifically affects operations such as password changes, email address modifications, and account deactivation, all of which can fundamentally compromise user accounts and access to communications. The flaw essentially creates a backdoor within the legitimate authentication flow that allows malicious actors to escalate their privileges without proper authorization.
From an operational perspective, this vulnerability creates severe implications for Matrix homeserver administrators and end users who rely on the service for secure communication. The attack vector requires only access to an authenticated session, which can be achieved through various means including session hijacking, credential theft, or social engineering attacks that result in session compromise. Once an attacker gains this session access, they can execute operations that would normally require password confirmation, making the vulnerability particularly dangerous as it can be exploited even when users believe they have secure sessions. The impact extends to the broader Matrix ecosystem, as compromised accounts can lead to unauthorized access to encrypted communications and potential data breaches. This vulnerability also demonstrates the importance of proper session management and the need for robust access control validation mechanisms that prevent privilege escalation through session manipulation.
Security mitigations for CVE-2025-62425 involve immediate deployment of the patched matrix-authentication-service version 1.4.1, which addresses the logic flaw through proper session validation and re-authentication requirements for sensitive operations. Organizations should also implement additional security measures including regular session monitoring, enforcement of secure session management practices, and implementation of multi-factor authentication where possible. The vulnerability highlights the importance of proper input validation and access control implementation, aligning with CWE 305 authentication bypass weaknesses and ATT&CK technique T1078 legitimate credentials. System administrators should conduct thorough security assessments of their Matrix homeserver configurations to ensure that password database features are properly secured and that session management policies are enforced. The remediation process should include reviewing existing authenticated sessions and potentially requiring password resets for all users to prevent exploitation of the vulnerability. This incident underscores the critical need for continuous security testing and validation of authentication mechanisms, particularly in services that handle sensitive user credentials and access controls.